Diffuse axonal injury at ultra-high field MRI.

Area of Science:

• Neuroimaging
• Radiology
• Traumatology

Background:

• Diffuse axonal injury (DAI) is a severe traumatic brain injury resulting from shearing forces.
• Traumatic microbleeds (TMBs) are key radiological markers for DAI.
• Susceptibility weighted imaging (SWI) is crucial for detecting TMBs.

Purpose of the Study:

• To compare the diagnostic performance of 3 Tesla (T) and 7 T SWI in detecting DAI-associated TMBs.
• To evaluate the potential benefits of ultra-high field (UHF) MRI for DAI diagnosis.
• To assess the impact of increased spatial resolution at 7 T on TMB detection.

Main Methods:

• 10 participants with known DAI underwent MRI at both 3 T and 7 T.
• SWI was performed at 3 T and 7 T with similar and increased spatial resolution.
• Two neuroradiologists independently evaluated TMB location and count.
• Inter- and intraobserver reliability was assessed using the interclass correlation coefficient (ICC).

Main Results:

• 7 T SWI detected 20-41% more TMBs than 3 T SWI.
• Hemorrhagic DAI lesions appeared significantly larger on 7 T images (p = 0.005).
• High inter- and intraobserver reliability was observed for both 3 T and 7 T SWI.

Conclusions:

• 7 T SWI offers superior visualization of small hemorrhagic DAI lesions compared to 3 T.
• UHF MRI at 7 T may serve as a valuable supplementary tool for diagnosing DAI.
• This advanced imaging technique is particularly useful in inconclusive or medicolegal DAI cases.